The risk of HCV RNA contamination in serology screening instruments with a fixed needle for sample transfer

AbstractBackgroundHepatitis C diagnostics involve antibody screening and confirmation of current infection by detection of HCV RNA positivity. In screening instruments with fixed pipetting needle, there is a risk of sample carry-over contamination.ObjectivesThe aim of this study was to evaluate the risk of such contamination in a proposed clinical setting.Study designIn the present study, known HCV RNA positive (n=149) and negative (n=149) samples were analysed by anti-HCV Abbott in an Architect instrument in an alternating fashion in order to test for contamination.ResultsIn subsequent retesting of the previously HCV RNA-negative samples, six samples (4%) were positive by the Cobas Taqman assay with a maximum level of 33IU/mL. The results show that there is a risk for transfer of HCV in the Architect instrument but they also show that the levels of HCV RNA observed are low.ConclusionsWe conclude that complementary HCV RNA testing on samples identified as anti-HCV positive by screening can be recommended because the complementary results are reliable in the majority of cases when either HCV RNA is negative or HCV RNA is positive with a level >1000IU/mL. In a minority of cases, with low HCV RNA after anti-HCV antibody screening, cross-contamination should be suspected and a new sample requested for HCV RNA testing. This strategy would reduce the need for obtaining a new sample from the vast majority of patients with a newly discovered HCV antibody positivity

Real-time PCR detection of Human Herpesvirus 1-5 in patients lacking clinical signs of a viral CNS infection

<p>Abstract</p> <p>Background</p> <p>Infections of the central nervous system (CNS) with herpes- or enterovirus can be self-limiting and benign, but occasionally result in severe and fatal disease. The polymerase chain reaction (PCR) has revolutionized the diagnostics of viral pathogens, and by multiple displacement amplification (MDA) prior to real-time PCR the sensitivity might be further enhanced. The aim of this study was to investigate if herpes- or enterovirus can be detected in cerebrospinal fluid (CSF) from patients without symptoms.</p> <p>Methods</p> <p>Cerebrospinal fluid (CSF) samples from 373 patients lacking typical symptoms of viral CNS infection were analysed by real-time PCR targeting herpesviruses or enteroviruses with or without prior MDA.</p> <p>Results</p> <p>In total, virus was detected in 17 patients (4%). Epstein-Barr virus (EBV) was most commonly detected, in general from patients with other conditions (e.g. infections, cerebral hemorrhage). MDA satisfactorily amplified viral DNA in the absence of human nucleic acids, but showed poor amplification capacity for viral DNA in CSF samples, and did not increase the sensitivity for herpes virus-detection with our methodology.</p> <p>Conclusions</p> <p>Viral pathogens are rarely detected in CSF from patients without signs of CNS infection, supporting the view that real-time PCR is a highly specific method to detect symptomatic CNS-infection caused by these viruses. However, EBV may be subclinically reactivated due to other pathological conditions in the CNS.</p

Endocine™, N3OA and N3OASq; Three Mucosal Adjuvants That Enhance the Immune Response to Nasal Influenza Vaccination

Annual outbreaks of seasonal influenza are controlled or prevented through vaccination in many countries. The seasonal vaccines used are either inactivated, currently administered parenterally, or live-attenuated given intranasally. In this study three mucosal adjuvants were examined for the influence on the humoral (mucosal and systemic) and cellular influenza A-specific immune responses induced by a nasally administered vaccine. We investigated in detail how the anionic Endocine™ and the cationic adjuvants N3OA and N3OASq mixed with a split inactivated influenza vaccine induced influenza A-specific immune responses as compared to the vaccine alone after intranasal immunization. The study showed that nasal administration of a split virus vaccine together with Endocine™ or N3OA induced significantly higher humoral and cell-mediated immune responses than the non-adjuvanted vaccine. N3OASq only significantly increased the cell-mediated immune response. Furthermore, nasal administration of the influenza vaccine in combination with any of the adjuvants; Endocine™, N3OA or N3OASq, significantly enhanced the mucosal immunity against influenza HA protein. Thus the addition of these mucosal adjuvants leads to enhanced immunity in the most relevant tissues, the upper respiratory tract and the systemic circulation. Nasal influenza vaccination with an inactivated split vaccine can therefore provide an important mucosal immune response, which is often low or absent after traditional parenteral vaccination.Funding Agencies|Eurocine Vaccines||Vinnova Research funds||Halsofonden||</p

Endocine™, N3OA and N3OASq; Three Mucosal Adjuvants That Enhance the Immune Response to Nasal Influenza Vaccination

Annual outbreaks of seasonal influenza are controlled or prevented through vaccination in many countries. The seasonal vaccines used are either inactivated, currently administered parenterally, or live-attenuated given intranasally. In this study three mucosal adjuvants were examined for the influence on the humoral (mucosal and systemic) and cellular influenza A-specific immune responses induced by a nasally administered vaccine. We investigated in detail how the anionic Endocine™ and the cationic adjuvants N3OA and N3OASq mixed with a split inactivated influenza vaccine induced influenza A-specific immune responses as compared to the vaccine alone after intranasal immunization. The study showed that nasal administration of a split virus vaccine together with Endocine™ or N3OA induced significantly higher humoral and cell-mediated immune responses than the non-adjuvanted vaccine. N3OASq only significantly increased the cell-mediated immune response. Furthermore, nasal administration of the influenza vaccine in combination with any of the adjuvants; Endocine™, N3OA or N3OASq, significantly enhanced the mucosal immunity against influenza HA protein. Thus the addition of these mucosal adjuvants leads to enhanced immunity in the most relevant tissues, the upper respiratory tract and the systemic circulation. Nasal influenza vaccination with an inactivated split vaccine can therefore provide an important mucosal immune response, which is often low or absent after traditional parenteral vaccination.Funding Agencies|Eurocine Vaccines||Vinnova Research funds||Halsofonden||</p

IL-2 release from splenocytes, stimulated with different antigens.

<p>Mice were immunized with a split influenza vaccine (Vaxigrip) containing the A/H1N1/Brisbane/2007 strain with or without adjuvant. The groups were immunized three times with three-week intervals. Splenocytes were analyzed regarding IL-2 release after influenza stimuli. (A) IL-2 responses against influenza A/H1N1/Brisbane/59/2007 (whole virus). (B) IL-2 responses against influenza A/H1N1/ California/04/2009 (whole virus). (C) IL-2 responses against influenza nucleoprotein-peptides from A/H1N1/Brisbane. Median and range is shown for each group and statistical significance compared to the non-adjuvanted group are indicated, *p<0.05, **p<0.01 and ***p<0, 001.</p

Mucosal influenza HA-specific IgA in nasal wash samples.

<p>Mice were immunized with a split influenza vaccine (Vaxigrip) containing the A/H1N1/Brisbane/2007 strain with or without adjuvant. The groups were immunized three times with three-week intervals. (A) Mucosal influenza HA-specific IgA in the nasal wash samples is shown. Median and range is shown for each group and statistical significance compared to the non-adjuvanted group is indicated, **p<0.003.</p

HAI and NT-antibody titers against influenza A/H1N1/Brisbane in serum after the final immunization.

<p>Mice were immunized with a split influenza vaccine (Vaxigrip) containing the A/H1N1/Brisbane/2007 strain with or without adjuvant. The groups were immunized three times with three-week intervals. The HAI and NT-antibody reactivity against influenza A/H1N1/Brisbane in serum after the final immunization are shown. Median and range is shown for each group. Values <10 in HAI was set as 5 and values <100 in the NT-assay was set as 20. Statistical significances compared to the non-adjuvanted group are indicated, *p<0.017 and **p<0.003.</p

Serum IgA titers against three different influenza stimuli (rHA, Vaxigrip and vaccine against influenza) after nasal vaccination. Median, range and response frequency in each group are shown.

<p>Abbreviations: rHA =  recombinant hemagglutinin, NA  =  Not applicable.</p

RESEARCH ARTICLE Open Access

1-5 in patients lacking clinical sign